The vast majority of roofs have one or more pipes extending through the roof to allow gas that has accumulated inside the building to exit the building.
A common type of roof pipe is the roof vent stack. Roof vent stacks and other roof pipes are vulnerable to attack from a wide range of animals, including squirrels, mice and rats. These animals have frequently been known to attack roof pipes, particularly those such as the roof vent stack that are encased in lead.
There have been a number of approaches to solving this problem. One known approach to solving this problem involves encasing the roof pipe in poultry netting, commonly known as chicken wire, or some similar type of wire enclosure. Chicken wire provides relatively poor protection for roof pipes because it is difficult to secure the wire in place on the roof pipe without damaging the roof. The chicken wire is also flexible and may be bent in toward the pipe surface by rodents, thus leaving the roof pipe vulnerable to attack through the chicken wire. The chicken wire approach also results in a very unattractive and unprofessional looking wire enclosure surrounding the roof pipe.
Another approach involves coating the roof pipe with a sealant in liquid or gel form that hardens into position on the roof pipe to prevent access by rodents. This approach may be difficult to implement because of the difficulty in evenly coating the entire exposed roof pipe area. Certain materials used for this coating may not bond well with the lead boot or other roof pipe material. The materials used for this coating may also deteriorate over a relatively short period of time, leaving the roof pipe again vulnerable to attack by rodents.
Another approach is shown in U.S. Pat. No. 6,244,006 to Shue et al (hereafter “Shue” or the “Shue Patent”). The approach in Shue involves a sleeve made of PVC pipe with a separate end piece attached to the top of the sleeve that is fitted over roof vent stack pipes. The end piece is secured to the sleeve and then both the end piece and sleeve are secured in place over the roof vent stack by gluing it in place or securing it to the pipe with a screw. There are a number of problems with the Shue approach. First, the two-piece construction of the Shue device makes it less durable because the glue or other bond holding the device together may degrade over time as Shue acknowledges in mentioning replacement devices in the specification. Second, the Shue device causes water to accumulate on the roof inside the cylinder and around the roof pipe, particularly where the base of the Shue device is glued in place on the roof. Third, the Shue device inhibits the flow of gases from the roof pipe by creating a vacuum effect inside the cylinder as gas exits the cylinder. Fourth, the gas vent holes on top of the Shue device may become blocked and prevent airflow entirely, and the Shue device fails to provide any other mechanism for gas flow if this blockage occurs.
Despite the existence of such protective devices for roof pipes, further improvements in devices to protect roofing pipes are desirable.